Iranian Food Science and Technology Research Journal
Year:2013 | Volume:9 | Issue:3|Papers Count:14

In this study, antimicrobial effects of Zataria Multiflora boiss added to sodium caseinate film on four bacterial species: Staphylococcus aurous, Escherichia coli, Bacillus subtilis and Salmonella intertidis was investigated. Disk diffusion method was used to study the antimicrobial activity of Zataria multiflora Boiss in sodium caseinate film.9 mm disks were prepared from produced films with different concentrations of Zataria multiflora Boiss. with 1, 2, 3 and 4%. Surface culture was done under sterile condition using 0.1 ml of broth culture of each bacterial (106 -107 cfu/ml) on BHI agar. Then the disks were placed. Diameter of inhibition zone was considered as an index of antimicrobial activity of the film. Statistical analyses were done by means of SigmaSDAT software and mean comparison was carried out by LSD test. Results showed that disks containing essential oils of Zataria multiflora Boiss. in each concentration inhibited growth of E.coli, Sa.interitidis and B.cereus. Since there was no significant differences between 3% and 4% concentrations for these bacteria (p>0.05), concentration of 3% is the most appropriate and cost-effective concentration with the highest antimicrobial effect. Only the film containing 1% of essential oil of Zataria multiflora Boiss. Made no inhibition zone on S.aurous, in the other word had no inhibitory effect in this concentration. But inhibition zones created by 2, 3 and 4% for S.aurous were significantly different (p>0.05). results showed that essential oils of this plant can be used as a natural preserving in composition of edible film for packaging of food products.

In this study, Response Surface Methodology (RSM) was used to optimize osmo-dehydration of orange slice. Effect of osmotic solution temperature in the range of 30 to 60oC, immersion time from 0 to 300 min and sucrose concentration from 35 to 65 brix degree on water loss, solid gain, moisture content, water loss to solid gain ratio and brix change were investigated by Central Composite Design (CCD). Applying response surface and contour plots optimum for osmotic dehydration were found to be at temperature of 30oC, immersion time of 229.2 minute and sucrose concentration of 65%. At this optimum point, water loss, solid gain, WL/SG ratio, moisture content (dry base) and brix difference were found to be 30.316 (g/100 g initial sample), 13.51 (g/100 g initial sample), 2.45, 2.77 % and 15.79, respectively. The result of artificial neural network indicated that the perceptron neural network with one hidden layer is able to anticipate the dehydration characteristics. This network predicted solid gain and moisture content with 5 neuron per hidden layers with R2 values of 0.937 and 0.959, respectively and brix difference and water loss with 30 neuron per hidden layer with R2 values of 0.961 and 0.942, respectively.

In this research effectiveness of immersing three types of contaminated pistachios fresh with hull (exocarp or epicarp), dried in shell and dried with hull from Ohady cultivar in ozonated water 0 ppm (control), 4 and 8 ppm ozone concentrations in aqueous solution for range of exposure times 0 (control), 2, 4, 6, 8, 10 and12 hours, to decrease of aflatoxin (B1, B2, G1, G2 and total) were investigated. Water temperature and pH were 10oC and 5.5 ± 0.3 respectively. For all samples, interaction between, ozone concentration and exposure times or pistachio type, were investigated. Aflatoxin (AF) B1 content was more and was reduced easily. Results showed that differences between the control samples (zero hour and/or 0ppm ozone) and treated pistachios for total aflatoxins and aflatoxin B1 were significant (P<0.05). For control samples, the means of aflatoxin reduction for B1, B2, G1, G2 and total were, 5.6, 9.7, 14, 6, 15 and 6.4 percentage, respectively and for ozonated pistachios were 32.7, 8.55, 30.6, 34 and 35 percentage, by 4ppm ozone concentration. The results for 8ppm ozone concentration were, 47.9, 12.5, 45.8, 43.9 and 44.4 percentage, respectively. The results indicated that the effect of ozonated water on reduction of aflatoxin content from the samples significantly depends on the level of ozone concentration and exposure times. The results also demonstrated that ozone susceptibility of aflatoxins to destruction were B1 & G1>G2 & B2 respectively.

Lemon is one of the most important citrus fruit and is consumed as fresh and dry. In this study the effect offruit moisture content on the size, sphericity, geometric mean diameters and kernel density were studied. Thebulk density and porosity were also evaluated in three different arrangements. Airflow resistance is afundamental parameter for designing an efficient drying and aeration systems for lemon fruit bed. Using alaboratory test rig, two sets of experiments were carried out: thick and thin layers. In the thick layer experiments4 bed depths, 11 air flow rates and 4 air temperatures were adopted as independent variables. In the thin layer theeffect of filling arrangements in three patterns: A, B and random, at 5 moisture contents and 11 flow rates onpressure drop were envisaged. Results showed that all the physical parameters listed decreased by reducingmoisture content. Results indicated that resistance to airflow through a column of lemon fruit increased withincreasing bed depth and airflow rate. In the latter experiment pressure drop decreased with a decrease inmoisture content. Airflow rate was the most significant factor affecting the pressure drop of lemon fruit in theboth experiment. Also the filling arrangement B has a higher affect on pressure drop comparing with otherarrangements. Three applicable models (Shedd, Hukill & Ives, and Ergun) were used to evaluate the pressuredrop data. The Ergun model, with higher values for coefficient of determination and lower values for root meansquare error, is the best model for predicting pressure drop across lemon fruit bed for the conditions studied.

Malting is a complex biotechnological process that includes steeping; germination and drying of cereal grainsunder controlled conditions of temperature and humidity. In this research malting process parameters werepredict by modular neural network with different activation function included, logsig-logsig, tanh-tanh, logsigtanh, logsig-identity and tanh-identity. Steeping time (x1) and germination time (x2) were used as inputparameters and hot water extract (y1), malting yield (y2) and enzyme activity (b-Gluconase) (y3) were selected asoutput parameters. The results showed that using perceptron neural network with tanh-identity activationfunction had the best result among all of activation functions to predict effective parameters of malting process. As well, this network was able to predict hot water extract, malting yield and enzyme activity (b - Gluconase) with R2 value of 1, 0.984 and 0.995, respectively.

Nitrite is responsible for some characteristics of cured meat products such as color, flavor and suppressingthe outgrowth and production of toxin from Clostridium botulinum. Despite all of its desired properties, nitrite isresponsible for the formation of carcinogenic N-nitrosamine. In this study, nitrite-free and low-nitrite meatcuring systems were developed to eliminate or reduce nitrite from meat products. Thirteen different formulationswere made including standard frankfurter ingredients with or without nitrite in combination with cochineal andpaprika as natural coloring agents. For example, control sample was with 120 mg/kg nitrite, low-nitrite samplewas contained 40 mg/kg nitrite and some samples were without nitrite. The samples were stored at 4oC for eightweeks. During the storage, color changes (L*, a*, b*) were determined and evaluated. Also, the producedsamples were exposed to natural and artificial light and their color stability were compared. In addition, thecolors of samples were evaluated by trained panelists. The results showed that the sample with 40 mg/kg nitriteand 0.002 % cochineal, the sample contained 40 mg/kg nitrite and 1 mg/kg paprika and the sample withoutnitrite and contained 0.015 % cochineal had no significant different color (p<0.05) from the control sample. Overall, it is possible to produce nitrite- free or low- nitrite frankfurter sausage with acceptable color.

The increasing tendency for health oriented products caused considerable research has studied onincrease and maintaining quality of different products. Sponge cake is one of the cereal products whichitsmain problems arereterogradation and lack of soluble dietary fibers which has many health benefits. In thisresearch, therefore, the effects of adding oat b-D-glucan on the physical properties of sponge cake wereinvestigated. Samples were produced by different concentrations of b-D-glucan (1, 2, 3 and 4%) with controlsample. Physical properties of samples including volume index, porosity, hardness, color and sensory propertieswere examined. The results showed that the addition of b-D-glucan up to 2 (%) softened the cakes withoutunpleasant changes in sensory properties, also increased volume index, porosity and color of the cakesamples.

Since the waste of agricultural and horticultural products is high, appropriate methods should be used to produce products with high quality and shelf life for export. In Iran a great part of fruits and vegetables are dried conventionally and farmer use So2 gas for preservation and color stability of dried apricots, but this gas is allergic and carcinogenic and effort to find suitable substitutes for this substance would be an efficient method to the health of the society. So, in this study 3 apricot varieties were selected to evaluate the drying quality and to determine the so2 replacement methods. The selected varieties (Noori, Khaybei 2 and Nasiri) were treated with citric acid, (0.3%), ascorbic acid (0.3%), sodium meta bisulfate (0.4%) and a 50% mixture of ascorbic and citric before drying and then were compared with control samples (without any treatment). After drying, the characteristics such as Brix, pH, moisture contents, browning index, acidity and organoleptic properties were evaluated. Results showing that the effect of variety on moisture, browning, pH, acidity and organoleptic properties were significant (p<0.01) and the treated sample had significant differences with controls. According to the obtained results the khaybei 2 veriety and treatment with the mixture of ascorbic and citric acids were selected as the best treatment in this study.

In this study, mathematical modeling of hot air-drying of thin-layer papaya (Carica papaya L.) slices with 5±1 mm thickness pretreated in osmotic solution (50% sucrose) was investigated. Thin-layer drying was conducted under three different drying temperatures of 40, 50 and 60oC at a constant air velocity of 0.9±0.1 m/s and absolute humidity of 0.6±0.02 g of water/kg of dry air. It was found that the drying process occurred in falling rate period over the drying time. The osmosis dehydration characteristics obtained by solid gain (SG), water loss (WL) and weight reduction (WR) parameters that increased with increasing immersion time. The effective diffusivity for papaya slices was within the range of 2.13×10-9 to 4.84×10-9 m2/s over the temperature range. The activation energy was 38.63 kJ/mol indicated the effect of temperature on the diffusivity. Based on the statistical analysis using coefficient of determination (R2) and root mean square error (RMSE), it was concluded that the best model in terms of fitting performance for hot air-drying of papaya pretreated in osmosis solution in all temperature range was Midilli et al. model.

In this study, the oil yield, fatty acid (FA) composition and the physicochemical and quality characteristics of Salvia macrosiphon crude seed oil were determined. The main fatty acids ranked in the following order of abundance: a- Linolenic Acid>Linoleic Acid>Oleic Acid. The n3 /n6 FA ratio and polyunsaturated FA/ Saturated FA ratio were 1.6 and 7.23, respectively. The FA composition revealed that the oil had great potential to use as nutritional dietary component and also was very susceptible to oxidation. The physicochemical properties such as Iodine (168.7 gI2/100g oil), Acidic (0.5) and Peroxide (1.9) Value, color (L: 59.22, a: -5.09, b: 22.94) and refractive index (1.4723) were also determined. Total phenol, tocopherol and sterol content were 165.22 mg GA/kg oil, 629.59 and 2540.6 ppm. In addition Oxidative Stability Index was 3.94 h.